SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb8fb8b26f8e810175f0e281274e1690c7ef5c6610a33293c5d8aa6177c80a89' 
  AND token = 'QIs+ZTsRcEL8DRvyYYpM/JfsK+OoKqG9SdV425/UR3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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