SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fef30fd84cc01293fd58f782bfac201d4e8452aee276ad5f0ec170155b28efe' 
  AND token = 'YMdpKxbsLjYHBNs5fL2W+MQ/Wh2FoigamewwYPj23Yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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