SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fea2c550eddb35292dca4d064f31348f099428c95a9a12ec8d5fb9117011702d' 
  AND token = 'MkS59eAyFo8TopmUDi+0SdU3XyZa+5jnl4G7WWxNe7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}