SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81de129a7047c7a799af7b0bca6daed52ec2d30791c48cf66f68af8380ccf172' 
  AND token = 'e1sap3QFI5zFmQTGyFEAHBG3lHdKc37dSO3rZoc3lnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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