SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd41f5ba112470b370e879de55cbd6e4686af937faa9c9598f2ccade6f1b134b5' 
  AND token = 'V+W4lDnyAMs5t1zIBvQww1NzPqFULYE9jCBPpZDP1IA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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