SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f12bfcc67b95128bc128e8e23086de7af1edc1b275436db0de53143c65e5f107' 
  AND token = 'QQTc+etsYhN6mJTDiDHO3zQO87fNM24V1LRgUuQG54M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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