SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ede7584b8ff970de80f9681348795ad5979a7a249641e1cb283c4a8c606bb8' 
  AND token = 'BNV8ji3jUbZ/iTc/p6lPFDc+t2xZi/ocqQy1IhJv8hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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