SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b42b646926f16109868871c9291705d2757c5c2cd3d7fd68a0a5c28b1d6af8a' 
  AND token = 'xFIK5nGeUZ+ETM+7RvryG43U8VXGBTbpnA+G/5fzvwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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