SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c68d041ba8d399ddd9000e42709de97b212843ccf7d85a54a5bc512fc6876f7d' 
  AND token = 'Z4T4d/VrkFXKky/QnPU0fu7tfvgDJcRcukqYyb6Z6Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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