SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89cbc3ddf3d789fc69d5083b66a12eec170a40ec72907a2a6a216aa595f01e7a' 
  AND token = '/zxWkI+PrYk/wdbKLymRLcKGZFjBpdtGAy75SVGzJkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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