SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f55369742e9b251b2feb55c6f927de650f063215a8041696cf3ef8d7093b94' 
  AND token = 'tiaLcGggAZz/wDVYzTC/7IEOONXzliPqHbyzYeTr+Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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