SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1be1d778c711cc223c743be5ef59158e62b766c59307b92e4fde05db9d460305' 
  AND token = 'bPsn+clgVOc3FIoVZqjsRid3hxBjqmsgfvIxC9TnkJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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