SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc3715456c1b88ce9633b49a68f78bf4af2d644bf52c4e72a9b9d94fe98be74' 
  AND token = 'K1qa5rlxmaZSUh7pSHSfJYw5ILpJtDLSe+zDOzHUGGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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