SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cdc73026c29864050752f719a7e54a9f2d8220cfe3784927ff6b8fd3173317b6' 
  AND token = '31hZrK3JQCaheU6dxeN8PyGggpGFNH69s+4SBiign3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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