SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b230a754422f8d329f7c7d52e64d12e96102158874f896c89981486c63ec4848' 
  AND token = 'sF2rjIC67gBqAnHzRYKkkg1FcB0LWJcSmLUwcdLlL2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}