SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd4f31e5b02ef42a583cfa92ac70a0006c74017fe807acc1917e1dd543cc6681' 
  AND token = '5QwlKKWwAtET91ZuaRn6wlJrSAiy4yXKF6Pyyb2Y3ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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