SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '274c8507787642e2961be9ead834f13e25e9dc8f6ce9dba4a1c6c40c8408b531' 
  AND token = 'Npmj9zlY8vJFk/312iLx6zDADGBw8P+wUkU3Gt+/fCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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