SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5856e859b797f515f8b5450c8266ceedd5f1ed521e4d4b145f80544c189869d2' 
  AND token = 'xmDTF8oeCUQNar3JfKTc2tUqf2Yc0nbRuIUpfCslJxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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