SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40fb7a7fd4633296bc499b2426f1fd1420fe7db25edfc915ed18f5fecea07624' 
  AND token = 'zztgKcl2W+cHRYCu1NymYfZJv5Zhq0Qp9A1vYTYlhms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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