SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705f8abaf731259096230fe9602934f570892102ab6f252be568a7dbbb77e753' 
  AND token = 'lhcFShebm/zMlAFobSy+M81mv12pbBJ6HmjQ7rQ8jgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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