SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ebe38933c3947fa2e2e5f1f34a59b7f0da294840777ae097d81e7d9fba4563e' 
  AND token = 'DRdWaj95bfQtUHPRcjqiRjmcbWFdrgxDrnYzebTEOZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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