SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d4faa425c834016ccacd7be22c0c4845d4bdfa8737cedd297b55d26962f993c' 
  AND token = 'hDBXD19ibpKFuLmrWy+yqWQ3pCatDgqqNakU+rjxRRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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