SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bcf769e73476c002712f9f0069c64a025764f1d44e3438854a8f453d785e952' 
  AND token = 'vP78libpnuq0rxiJYd6ERhudff8IPhO0gHLByijVcZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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