SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c42bbd11a146540fd8d983aafb49568a462d172bdaca1d68d93412809ac3d40' 
  AND token = 'v6Vwdhl7tunF5ItIBRQa7IKV+PgQZFD/NPsGIhNCAAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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