SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0c3be5f68cb5e8601bdfa54ca03dca91021a018496205bf19495d925814361cc' 
  AND token = 'C+dJ3ONalKjFgm31w/Rr8LMU721DXNe0H/XE+zAYZzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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