SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d5b39a8f1431e7947f0a43f7c2cb30b320d4adafda97b5c67afaa463371db1a' 
  AND token = 'ubvo7jZFXQ+EVVFde0/fECtKRPbKfd1xhVIWhivZ1FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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