SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6dfc8eca9e30a009cbafde1468ecb027a3b64bbbb64dd2beb08af8dce01250b' 
  AND token = 'LGKvfCafO7m866LVgGzpKnLY86gwtvTAm8ge98WDst8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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