SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ba570bb0f1c72ac828d122a065d1fab9239f1287837cd689891e7362f20c97' 
  AND token = '3JR49q0v1YmxFCCdZloPLezuYD7AKQTTd4KNyY45Wjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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