SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9e5198dff2ac6f7134666e69c9d4b05b7ddb3dac811b128751565381fc24a40' 
  AND token = 'uOTXiLQWSTyaXbEDC8llYn+YLhtZjkA4HaVxtc5s6c4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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