SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d36cfac228f48ee3d193436b0450cf969ee97eb2638d9c35ed051d91bb8438c' 
  AND token = '6awgG7MEVBeiTJ/GpZHn1jwq6W7bkyBpxakaRk3AGYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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