SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f7b6de72576b0f4438eddac745d7a2362271b468f1d5981f528a0964308f16' 
  AND token = 'k+ahTEbVozvpQTC2MpbQglQTJ6imK4AqbQwmGu+Y91Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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