SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ace252e5a6c61746cc569f7ce5960290003772b6948d5bccf02c76111ff07f3b' 
  AND token = 'tRLZRDxwI7JOyj/EBWqQiaEvkeDHAAHWn942ukfZILs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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