SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '747a640f90168666c26b1ac587bf810022b9325de9456c12e2e029d536cc5f39' 
  AND token = 'Fylu6xOjrSsR2pFDzct9CzM9Ztcm3HysNmzax6AmvTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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