SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efa2ea500a7a940de71ba15f0fd0d7e52daf2c82229a1ab12fd115d59a1e0431' 
  AND token = 'RnxD9SR4EZiWRjVJ0nma4v1JDrVFj4On/9mRM6Gumnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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