SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb37224128b4bf21801de19a294cd32609bf52a2814d56ca89b583dae779b5cb' 
  AND token = '5QlHp7GvfrR7DtqNHWTxEbwDnYEnJAtexhdh/DnX058=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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