SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49fb8638225c8dfa337040c86b43a272cfaedda4e787232d53de56da6fd9c71' 
  AND token = 'kR5OPelqSzVX4ilsXcfkzjl8TcPr7ThSMFhhmBZWccw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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