SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4189fb6df888315ae2788638b2f5018831a237a665821083a540389814035fb0' 
  AND token = '3qWeQoHFyIcDL/wPfZR7+eAybsBenYAtduQmSGOf6wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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