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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3b1df4b74bed4898b14c1952ff4f1fd42d047d16c6c05e70d6a77b307ff338cc' 
  AND token = '+JMb4WU9aP/MQcTzwH8DEsH8qeaeg9k5VpgQetfWReY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}