SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b967a00d0d91bf8de652e1c0bf6b44bade561f4f409c640c7de7b450e3726485' 
  AND token = '/mHu2BPBY05zPidUJy8nCnBblJwPpeJ9wksAS9OpF3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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