SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd91c19de8a1bea10cd7b755275ed32f7e2f28a4f028e90350f545b98f61cf4' 
  AND token = 'WCRNXzcm9NIXOT88HdGXLygME//YUqDWecAaYu34Ypw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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