SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c2d9aaadacac61abf4cb9e5e6ecff21c77db757c2310782931bac1c5352aeb0' 
  AND token = 'WUdBLATjgwOl158gQcuIe+NzUuOxbkrMXouQqZXENMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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