SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3115fa261f582aa770bda493ae3929158d3f83835c4c6c6694a22beb211ab8d3' 
  AND token = 'SZgXGtqg5w2ii+ozBhoGQBAkeSAbwmOUOcHkS+EnJQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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