SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ccc16e00bb858b4b0f7f1faf2d10c648ac852e339248ffac701e6a72313aa57' 
  AND token = 'h6lbNt//5rcPdJ/1YMlpSXVGZJgOiDrXz5XzL8sT7Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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