SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35955b36a78d339b917cbf55d502ba998ddb276b2e4dc9b84dcb73f4293232f' 
  AND token = 'NeUpk/j9WS8ndZbdEt0hj9oyi6ia72w7V1QC7UuWvI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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