SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0d483b7ab1fe9db7fa9a234d52699b569622271d991b0ea9556263f8e0b1bc8' 
  AND token = 'JwunUXovLFApT+PliMe3hfA+13mSc/nMlvhuzzrZoI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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