SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2141bdff5327b77d8dec87334e40a6286a730731096c8b5497d0f97f75d90145' 
  AND token = 'qd5UIaXl2eZkQzfJJ45jRKxEZTgypGXyRS/FxF2/vA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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