SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23c9509d3001c85ba4941b73f89bed24b32802dcbad45ac677498defcff46a70' 
  AND token = 'jgFeVCek1bXhb55WZGxFSlf8DJPp1RzO66aiulbN/mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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