SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c68e3025231c07427f65e8dfc46930bb2559eca1c04dbcdb28816bd3fa2904a' 
  AND token = 'rqPrwmCez+lHzrtSRrGBYMTBR1MPByUwsqohoQMv/1U=' 
  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"
    }
  }
}