SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '631d59424f476f6229b6df50db67cc67dc3bb280e807142aea7b709c8812b832' 
  AND token = 'lf2O/6XCcYB8ujFbxWIGfZ+bpmhjLu5m/iZF7AyRTg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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