SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4d7d0bf4567fc3610a1b5c60d1f7952d8139298bccd62f8e9219f4dca7ea5332' 
  AND token = 'Vbbxm/PV10gzAyE2pNnp2tErCQyv9XO/sJ6gnhJtYMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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