SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a34b0ba7cfdd28e65933bf7cd83bd4972c6d8b9d2516887b32a48d2335931f58' 
  AND token = '0zhj+EQpVuYFuwFOlVXhSKJ/kU9XbHc0KF5t8NsVN8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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