SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6631c33e308faeb99cb02a4349b1fe8f76759dbab0285f1d97dfea8bccd9497b' 
  AND token = 'mByR/5ORbZbP2lXO1xl1rX47suRRHsEtnlD/+5q0Wcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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