SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c979040be7b6fc1fd69662205d10e0951bd1dc61857cbbb350ca430908227fa8' 
  AND token = 'qkzuWmBdOVDZ+rizhuE5z2tOyjHSRUdAPXnZNWDVugY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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