SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '576b81229cd1639c1bf32c960d78e2f1a4a2575c18463d1cfc9a887d72a982c5' 
  AND token = 'vNfuOJOF6+NhU0VzIPW+jiFtKn+5WFHI8i1BuOjwYtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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