SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4423cad0707237adf60158c947bf2f87198b9b98460d0b35fd02ee839fc0a21e' 
  AND token = 'aiZFHjgX3Loz0jVJLpq0ogK6xfndoWu9kPqGmcfe9Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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