SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1260423e152a043d14e1be80afb534ea6afac4528032ec680a2939404ddbbb0' 
  AND token = 'Fmg0Je6EEc5HFo9dI/y1N5AMsuHFrq5Nk16xgJtUHIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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