SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21992a3ef7d8c75b5febbaf78fa6e14c0a4103d52fe80c52242b1af0f9883a60' 
  AND token = '78nRu0/0d4DYkndhcMXQZqRzvxGmEOffKcRYHrVe7KU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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