SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1a9bc41bba81a55d77550adf248acd7ad8bbb391b58aacfb3a1fc57a78542a1' 
  AND token = 'SVUw7zurs7NAcAsk1WOwt6qiUvJ7vo8iZXr1vZQrysg=' 
  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"
    }
  }
}