SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b90d9c71107bebaf4458041b62c4100d71852e2d1ea09da9bcd09128c40d46dd' 
  AND token = 'C0L0ifpIHYWaHJKXkq7hKbKuNQFiIg9GoetOVCqi6Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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