SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2f304176f4f3d4b98e79b7057094e01658078be88988b6a83eb675bfd682be5' 
  AND token = 'eEzGTIq/xloGkY/2YLZ4skRVmc6vN2UQP0LPUSkHwVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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