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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd971b5b84eaca0e90ea0d8546cadba0838b5fe463bc59f60cf6441aea72a727' 
  AND token = 'oD8/Lw8hiDHlR1q1T3jR//yNQHcoGf9wbCbFxvsQ6xY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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