SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f659142415f6913b3b8946b26979e0804cccf132599621bd117c6af558e3b783' 
  AND token = '7ahrdT6FehO5uzpKTigiR6tKSQz1C6PCqU9M/UGj/JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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