SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c1c7094d000dd581d366531dd1b51fb2bb23deeb318754bc51f80aaf2d7f496' 
  AND token = 'QdZCqOaeQ/ynZoqrHwhGLY28CZ85M1jPn/jyM/z+3Y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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