SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a91a15aed689d93b88fb4dc3556041a771808df68f109e56e1c4951db28d7e8' 
  AND token = 'GtvZTeposAl+hTCq+mZNCgOfKTCJeBzJj4I00CnWsHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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