SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59b0bff855b423a7578307bd82f13ab99396f27c9dec3fa55d1fd8fe465fbc4e' 
  AND token = 'jWRjpwIUFf1S+GsnMSM+v+ugGhqnv2QUvNub6Z7yCG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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