SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff78b27f8fa12618e83cf559f7e09e0715ca8f9c872c5fde098aa965a40c524a' 
  AND token = 'Zz7WQq4AjXq8Vl1shOXqpTYa+/C33JBmItYf0SEEXF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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