SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1544f2b49180889e8409bcd29852333e69c7bb4fe7c48bdc5c3d3df815c9c1cc' 
  AND token = 'wFKCF9BstUzmQLMBSOrAl4SMJ0RUQDnHVNjjKoZnGdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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