SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412061db26901d3b6874142b3f66941c378c2543fa054a25d46f09fbb70ce591' 
  AND token = 'FcMJURhW1kwwH5ZfntG4vTEvVlZyEQYxtLuyMZ5sUwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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