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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73c217e7d1bd12167c0c0c8c87cae4610e28730eb9d7bb9b266f1a9292307c67' 
  AND token = 'MyW9fC30UbbLIVFkdxIE43vmZJrnHYcYsQYA1chBNI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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