SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48c6f854e5a1a92438fb51b562960d27dec12c4b32776a35d0c561c92ad4fe3a' 
  AND token = 'j++sqgISJvMncIi4RPJTdFjIdiOuJgxVOFCKoXxBrCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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