SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b30e6f75a0f4040858f9a7a2e7d9e19da42499576588e1d60b6cc099ee20425e' 
  AND token = 'rrsNrfWB7xFNIm2f+WboL8FKTxFqzvuQ9o8//FozTvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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