SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4925688519ec604fb37d20c670f7a2dc16002a871a4e5c861b221776921958f' 
  AND token = '3dTh1k3FZQBCK8C1X3QF4CoUorAJ6Q3Rmn4ELG79I6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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