SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79496b32c87de37db8f356a1480dcc5fe485243a31be14101354e6a11ac90150' 
  AND token = 'UCI6ON7euRWTavsQZCBwqvUEv5cgavgLybeGN6CH54A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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