SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a028b327603612cf4d2dac51c79c598c506b5dae55082f9ea9f35d5d39fe58' 
  AND token = 'YVv3nwiHwnUX9WSUujjz+e9umgruxtOYqR7JGnnXjnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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