SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8062f3571beb04284fcd07d7347d180b2a5db57642194e5b268a4fadc57c9a5' 
  AND token = 'd1fo+YG4pVWVwkCIVAYgk4bWXvzYnth+NAK3tKHhtFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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