SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '290c6f13e04fae3c8f0126b5a01d4a73975ad02a4db66e54f768d5553c34c0b4' 
  AND token = '+cQ5jAbQqUai1lB44LJZkjPESrHKzVwYofl8dTp2J1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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