SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53493db3c40e17579dc5d89e21d7ccf98426e809d1fedddbcd41caaa4d19937b' 
  AND token = 'DnQlU8TtLwjVHQHQLxOcRcsH50oSpsDPm0mbVs3tWbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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