SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31652eeeb35b6772c4957f271b5694c911e020386c874631407e6c35948a3d26' 
  AND token = 'IYMk7IT39LyvwY/80kUzk817QoQ9j38p2tD6STKDAx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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