SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10fb18bd9ea8809047c65acc654826d13bf48b40762dca3a357ebdaef175c2da' 
  AND token = 'qeBwbiT6iR+JLiSY5IqXJQqrF4IU+gKEugIvcbNZClE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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