SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '24b6aeaab6033187193c5d8d092df219499bff037ae294c27f57a26856c26f71' 
  AND token = 'vdB6uOjYhMeNKSQFckXSUDYv8t/FViZ7DEqzErZEmUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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