SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2014eebd4080ba5afb07fc6b8584033b8cf7740d5ac5fb2b8d6f576901d0f1ce' 
  AND token = '8cpUkdC/rUmRXjq2UpQNIZ3J/Au1GkCxav0Jz9hyBiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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