SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd185882795c27c10dcc6ee54ac8139694ba92d2542e546dbe4f9ffb1db5562f' 
  AND token = 'QZThV+N+72XQh2MUpoyYTQxb3BYHwcgknh2I8VEbwsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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