SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3636564e481b469a14dc4546634206fc8e56f2590bf67f28d2554f6a0b7d8400' 
  AND token = '3aqNgrGeTYZnVTphx370zyGSLA714hZp884veKBE9eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}