SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46caeef6488aa0b5838e861a48dc94281a48da947f92154e08cc1f798f515e66' 
  AND token = 'gZuEMyKBALtag3iS0k2/XJd2aXnJeMkghB6EZfPw3qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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