SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c0304bd42a7ba6f873f1402ae44c9f3894996f3d421cb5befe7c9e916fe8bf4' 
  AND token = 'ntsDJonbkAGQGgL3/iIooUONzpnIdMhd0oCk98vRURM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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