SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79e88f8d3ec1bad3202d5e993553446fbe477013acb00f46d41ff69567de79a8' 
  AND token = 'E5y7tF/Q3ZOvPJQ8XBuDn/pqnnPyWWioshVwDjbH3mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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