SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5a91ff22967f4615d2e25e8d7767ebacc24e375114afe0e080298e7d760fd5b' 
  AND token = '2oz/DdYnpcEVaBinXSuiHOgtcO6BBys1KdQj2OfJVbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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