SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795b5260f92ce6a6896bf1564436672050092254d3526d4b6a69cf71e935692a' 
  AND token = 'ZlbLn5vLdOcUU2fkh5V57HG+KDlkysL7AiybKdO1374=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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