SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b804923d35b4fe7333e346ec16c009b61819e358a076a3ad09c4071ac42f87fb' 
  AND token = '+4pg7eMx1qFN8QXt5kxfwl54xEkRlmyg98EgUabAmTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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