SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce39460227f053d460db537ba70feea27a39853741030af38676577c8ab44ad' 
  AND token = 'CXiGsbcaTNXFpjpMU6701YE1sr/6u0+0ds+zEfXq7/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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