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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df766774db93c4c33f3a399cf080d1f7f1d5ac4c7cbdfb4682984b0ac3ed3d9b' 
  AND token = 'nCqET0L5MkOWqY7HagzhFmYdSdyCQihNTnfjZRoMscM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}