SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '924c447ba78cf916325b6064f46311665075d78a25f5fe2d7f027dcbb6b81786' 
  AND token = 'eTZYjh+0qb8mtD8mp2qSO7HNxN97HvQvxrrIVJBQ+tU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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