SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6298a14e857100bcd1dc6671ded0bbae060c6fa388f81c9ecd81a10dcfc046dd' 
  AND token = 'MRNwmPGTpx/vDvsmIQ3JYPnEXpWHJKY7n89NLbz0tqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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