SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d03381e16ba0ad2a511b1f764f82341fd9f8ff118fa75896ada5594c972d4bb' 
  AND token = 'fi1O6ymaDEy+ymmyofXaK2reWRop7eEg7uHeAUqsXF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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