SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f45c6a153a274e5a6c93658dbb2fc2d4af5403477e6540cb6456272e770be5d' 
  AND token = 'wHetjTDi15wP+9NkQXiKdjXhko9Uq89gVxOoqQXVBSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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