SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6a18c03012bec31924c74e55f32ab3b537d33c1180bca1851d58f7848491201' 
  AND token = 'jHHumXzjohVFlQWjr5J+2qK+Wj07tg0gIOgEh8yrZgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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