SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6d1c7ce5c46b7f2353335965495dfd4a8b21f9023e7eba19af39c0f4324a179' 
  AND token = '83vYHDuWBL7vnehgzKB2hbWtWwhDQ6XJhGZbI/SsnEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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