SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f09ada47152a9b49fc936b4c494cd2d2c5447d0470f8b8967eb0403f53a301' 
  AND token = '2CKwmngz/Jk/Vzoe29OrxVGGjK539XptGhqNJxHbZck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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